Outdoor power equipment includes such devices as mowers, trimmers, edgers, chainsaws, brushcutters, blowers and the like. These devices are often used to perform tasks that inherently require the devices to be mobile. Accordingly, these devices are typically made to be relatively robust and capable of handling difficult work in hostile environments, while balancing the requirement for mobility.
Powering such devices could be accomplished in any number of ways. However, for outdoor power equipment that is intended to be mobile, and for which the emissions (i.e., in terms of noise and/or pollutants) generated by the device may also become an important consideration, electric motors are often popular choices to power such devices. Given that outdoor power equipment operates in hostile environments, a BLDC motor may be a popular choice as the electric motor for such devices.
In this regard, BLDC motors do not include a commutator and brush assembly and thus there is no ionizing sparking generated by the BLDC motor and there is no brush and commutator erosion. BLDC motors use a solid-state circuit for generating an alternating current from a DC electric power source (e.g., a battery). BLDC motors may therefore provide a longer life, reduced noise, and increased reliability relative to DC motors that employ commutators and brushes. Furthermore, BLDC motors can operate in entirely enclosed environments, so they may be isolated from dirt and debris.
When BLDC motors are used to power working assemblies (e.g., blades, chains, fan assemblies, trimmer heads, etc.), the working assembly is typically rotated or otherwise operated responsive to the application of power via some form of operable member such as, for example, a throttle control operator. However, for some of those working assemblies, the rotating member is desirably provided to rotate with a relatively low friction or drag during operation. Thus, when the throttle control operator is released, the working assembly may continue to rotate for some period of time due to inertia. To ensure that the working assembly can be slowed within desired periods of time (which may be defined by safety standards), a braking mechanism may be employed to slow and stop the working assembly.
Two main mechanisms exist for slowing and stopping the working assembly. First, hardware only mechanisms may be employed to stop the BLDC motor. Second, a combination of software and hardware components may be employed.